Composite parts and structures such as those used in the automotive, marine and aerospace industries may be fabricated using automated composite material application machines, such as composite tape lamination machines and composite fiber placement machines, all referred to herein tape laydown machines.
Tape laydown machines may employ single or multiple composite material application heads operated by NC (numerical control) or computer numerical control (CNC) controllers that control movement of the head as well as ancillary functions, including applying and cutting tape “on the fly”. In aerospace applications, these machines may be used to fabricate a wide variety of composite parts, such as flat spars, stringer charges, wing skins and fuselage barrel sections, to name a few.
Composite parts of the type mentioned above comprise multiple tape plies of varying thickness, complexity, and fiber orientation. Application of the tape is broken down into sequences, each of which may comprise a single ply or one or more individual pieces called ply segments, also sometimes referred to as ply “doublers”. The ply segments in a sequence (layer) often have differing fiber orientations, but may have the same fiber orientation. All ply segments laid in a sequence are normally in place on the part before material application proceeds to the next sequence. The part is complete when all sequences have been placed.
Path generation software may be provided that automatically controls and coordinates the movements of multiple tape application heads, including the order in which ply segments are laid down. This software partitions the ply segments and assigns tape heads to lay down particular ply segments. The partitioning process and tape head assignment is selected by the software programmer based on a few simple rules, personal experience and/or intuition. In some cases, the programmer may choose tape head assignments that may result in one or more tape heads being idle for periods of time, thereby reducing layup rate and adding to the time required to complete a composite structure layup.
Accordingly, there is a need for a method of optimizing task assignment for multiple tape heads which increases the rate of tape application and reduces the time required to complete a layup. Embodiments of the disclosure are intended to satisfy this need.